Acute and chronic neurodegenerative diseases are the most common neurological disorders in human and affect millions of individuals worldwide. While the specific clinical presentation varies among such diseases, their common feature is neural cell death. Yet, despite major advances in the understanding of neural cell death, effective treatment for these diseases remains one of the foremost challenges for medicine today. The transplantation of embryonic cells into the diseased brain in human has emerged out a mere theory and is possible as a practical application. This advancement, however, has raised important ethical, technical and immunological concerns. Studies have documented that neurogenesis occurs in the adult brain and that endogenous neural stem/progenitor cells (NSCs) respond to neurodegenerative diseases, suggesting that it might be possible for dead or injured neural cells to be replaced by endogenous NSCs. In this regard it is especially interesting to know the biological behaviors of endogenous NSCs in response to neurodegenerative diseases. Understanding the mechanisms underlying these changes could lead to the development of new strategies for treating neurological diseases using endogenous NSC pool.